Process for preparing a phosphorylated alpha-olefin polymer

ABSTRACT

A PHOSPHOROUS HALIDE (E.G. PCL3) IS PRESENT DURING THE FRIEDEL-CRAFTS POLYMERIZATION IN A MONOCHLOROALKANE SOLVENT (E.G. ETHYLCHLORIDE) OF AN ALPHA-MONOALKENE, RESULTING IN THE IN SITU FORMATION OF A PHOSPHORYLATED POLYMER. FURTHER REACTION OF THE POLYMER WITH A POLYAMINE CONVERTS PHOSPHORYL GROUPS TO PHOSPHONAMIDE GROUPS, YIELDING A PRODUCT WHICH IS USEFUL AS A LUBE OIL DETERGENT.

United States l atent ()ffice Int. Cl. C07f 9/28 U.S. Cl. 260-6065 P 11Claims ABSTRACT OF THE DISCLOSURE A phosphorus halide (e.g. PC1 ispresent during the Freidel-Crafts polymerization in a monochloroalkanesolvent (e.g. ethylchloride) of an alpha-monoalkene, resulting in the insitu formation of a phosphorylated polymer. Further reaction of thepolymer with a polymaine converts phosphoryl groups to phosphonamidegroups, yielding a product which is useful as a lube oil detergent.

This application is a division of application Ser. No. 629,929, filedApr. 11, 1967, now US. Pat. No. 3,650,- 953.

This invention relates to novel phosphorylated polymers, to their methodof preparation, and to the reaction products thereof with polyarnines.The invention also concerns lubricating oils which contain thesephosphorylated polymer-polyamine condensation reaction products.

Today many passenger cars primarily are used for driving to and fromwork, for errands, and for other short trips. This type of drivingrequires many stops and does not provide for full warmup or utilizationof the automobile. Engines are so lightly loaded and operated sointermittently that rarely do they get warm enough to operateefficiently. The fuel used in this type of engine is, of course,gasoline, usually known as an easily-burned fuel. Gasoline iseasily-burned if engine combustion chambers reach a high enoughtemperature and the fuel therein is properly vaporized and mixed withadequate oxygen. In such combustion the gasoline is completely burnedand only harmless carbon dioxide gas and steam are formed. However, ifthe engine does not operate long enough to heat its jacket Water andcrankcase to at least 150 F. some carbon dioxide and steam will blow bypiston rings, condense in the cold crankcase and form liquid carbonicacid which rusts iron and steel.

When the engine is cold and operated at the low speeds characteristic ofshort trip driving, combustion is insufficient and incomplete. Underthese conditions the gasoline is only partially burned, and much carbon,carbon monoxide gas, partially-oxidized fuel, and highly corrosive fuelacids are formed in the combustion chambers (in addition to the normalcarbon dioxide gas and water) and blow by piston rings to foul thecrankcase oil. The material resulting from incomplete combustion ofgasoline causes numerous engine difliculties and sometimes expensivedamage when collected in the crankcase. Examples of the damage thatresults, are sized and battered hydraulic valve lifters; worn cam lobes;stuck piston rings; high piston ring and cylinder wear with consequenthigh oil consumption and oil contamination; corroded bearings; scuffedpistons; clogged oil pump screens which may lead to engine oilstarvation; burned out bearings; and piston seizures. A modern lubricantmust therefore prevent deposition of solid products on the surfaces ofthe engine which normally come in contact with the lubricant.

Another source of trouble from deposits in internal combustion enginesis the additives which are conventionally incorporated in lubricants.Particularly, this is Patented May 15, 1973 the case withmetal-containing additives, for example, the organic, metal-containingsalts which are incorporated in the oil to increase the detergencythereof. Whenever oil is burned in the engine (as occurs with the oilfilm present in the cylinder wall during the combustion stroke) anymetal-containing additives present in the oil may form an ash which ispartially deposited on the various surfaces of the combustion chambers,spark plugs and valves. Accordingly, it is an object of this inventionto provide a lubricant composition which is compounded with metalormineral-free detergents.

Still the major donor of engine deposits is the incompletely combustedfuel, particularly the metal additives contained in the fuel. Theashless detergents of this invention provide for inhibition of sludgeformation in the engine and, further, dispersing of the sludgewhenformed. For many years, the detergent additives which are successfullyemployed on a commercial scale were organic, metal-containing compoundssuch as calcium petroleum sulfonate, calcium cetyl phosphate, calciumoctyl salicylate, calcium phenyl stearate or the potassium salt of thereaction product of phosphorous pentasulfide and polybutene. Various ofthese detergents act by reacting chemically With precursors to formharmless compounds. Others act to prevent flocculation or coagulation ofsolid particles in the oil and maintain the same in a state ofsuspension as finely-divided particles. Still others not only performthis dispersant function but also effect the solubilization oremulsification of the sparingly soluble monomers in the oil and therebygreatly reduce the rate of polymerization. In the latter case, suchpolymer materials as do form within the body of the oil are smaller insize and can be peptized or dispersed in the oil much more readily thanis the case with the large polymeric particles which are formed onexposed engine surfaces or in droplets lying within the oil. Detergentscapable of performing the dispersant function as well as thesolubilization or emulsification, are preferably employed wheneverpossible, particularly in automotive engines to be operated under citydriving conditions.

It has now been found that a normally liquid, base oil-solublephosphorylated polymer compound essentially of polymerizedalpha-monoalkene having from 3 to about 30, preferably about 0 to 21 andoften at least about 12, carbon atoms, the polymerization of which isinitiated using a complex of a Friedel-Crafts catalyst and a phosphorushalide in a monochloroalkane solvent, can be reacted with organic aminesto give a polymeric phosphonamide which is effective as an ashlessdetergent. Phosphonamide is here used to include amides of trivalentphosphorus as well as amides of pentavalent phosphorus. Thealpha-olefin, or alpha-monoalkene, may be the only monomer polymerized,and in any event this olefin comprises the major portion of themonomers, or there may be employed, if desired, a minor portion, forinstance about 5 to 45 mole percent, preferably about 15 to 40 molepercent, based on total monomer, of another, dissimilar, olefinicallyunsaturated copolymerizable monomer having from about 3 to 20 carbonatoms preferably about 4 to 10 carbon atoms. Accordingly, thealpha-olefin often provides about 55 to or even mole percent, preferablyabout 60 to 85 mole percent, of the monomers polymerized.

The alpha-olefins, or alpha-monoalkenes, of the present invention can berepresented by the formula:

ing of hydrogen and alkyl, including cycloalkyl, and the total number ofcarbon atoms in the alpha-olefin is from 3 to about 30, preferably about9 to 21. Preferably, one of R and R is hydrogen and the other is astraight chain alkyl to give a normal olefin. The choice ofalpha-olefin, their ratios, if more than one be employed, and the extentof reaction are such as to give an oil-soluble polymer, and often thetotal number of carbon atoms in the olefin reactant is at least about12. The alpha-olefin can also contain minor amounts, preferably lessthan about 10 percent by weight, of ofher, nonpolymerizable hydrocarbonssuch as saturatedhydrocarbons and aromatics.

As noted above, the alpha-olefin may be copolymerized with anotherolefinically unsaturated monomer which is dissimilar to or differentfrom the alpha-olefin. By dissimilar I mean falling outside thedefinition of the class of alpha-monoalkenes described herein. Examplesof such other monomers include hydrocarbons, such as styrene, vinylcyclohexene, vinyl toluene, indene, butadiene, etc., and otherunsaturated materials as, for instance, linoleic acid, methyl oleate,methyl methacrylate, acrylonitrile, etc. The major requirement of saiddissimilar monomer is that it be oopolymerizable with the saidalpha-olefin.

A complex of a Friedel-Crafts catalyst and a phosphorus halide isemployed to initiate the polymerization of the essentially alpha-olefinmonomer. The phosphorus halides used include compounds of the formulae,PX PX POX POR'X PR'X and PRX, in which X is selected from the groupconsisting of chlorine, bromine and iodine, and R is a monovalenthydrocarbon radical containing up to 16 carbon atoms. R, for example,can be alkyl, aryl, aralkyl, alkaryl, alkoxy, aroxy, alkaryloxy orcycloalkyl. Examples of such compounds include phosphorus trichloride,phosphorus pentachloride, phosphorus oxychloride, phenylphosphonousdichloride, ethylphosphonous dichloride, benzylphosphonous dichloride,xylyphosphonous dichloride, dodecylphosphonous dichloride,isopropylph'osphonous dichloride, normal butylphosphonous dichloride,tertiary butylphosphonous dichloride, tertiary octylphosphonousdichloride, and the bromide and iodine analogues thereof. The preferredphosphorus halides are phosphorus trihalides, especially phosphorustrichloride and phosphorus tribromide. The molar ratio of polymerizedolefinically-unsaturated monomer to phosphorus halide residue in thepolymer may be about 1, or less, to 300:1, preferably about 1 to 50:1.Thus, the polymer may have about 1 to 300, preferably about 1 to 50,molar equivalents of olefinically-unsaturated monomer per gram atom ofphosphorus in the polymer.

The phosphorus halide, which is supplied in solution with theFriedel-Crafts catalyst, as will be more fully discussed hereinafter,performs a dual role, i.e., as initiator of the addition polymerizationreaction and as phosphorylating agent of the olefin polymer thus formed.

The phosphorylated polymer, which is to be amidated to form thedetergent of the present invention, can be prepared by subjecting thealpha-olefin and the dissimilar monomer, if used, to a polymerizationtemperature of about 0 to 50 C., preferably about 0 to 25 C., in thepresence of a strong Friedel-Crafts catalyst such as aluminum chlorideor boron trifluoride. With the catalyst is charged the phosphorushalide, such as phosphorus trichloride, in an amount sufficient for insitu formation of a phosphoryl halide derivative of the olefin polymer.

A monochloroalkane solvent for the catalyst and the phosphorus halide isemployed in the polymerization reaction, the solvent also functioning asa co-catalyst for the reaction. The monochloroalkane has 1 to 4 carbonatoms, ethyl chloride often being preferred. The strong Friedel-Craftscatalyst will generally be present in the catalyst solution in aconcentration of about 0.5 to percent, preferably about 2 to 7 percent,by weight, and the amount of the Friedel-Crafts catalyst employed isgenerally about 0.1 to percent by weight, preferably about 2 to 15percent by Weight, of the monomer fed.

4 The phosphorus halide will generally be present in the catalystsolution in a concentration of from about 0.002 to 0.1 mole per ml. ofcatalyst solution. At all times, the phosphorus halide concentrationshould be less, on a molar basis, than the Friedel-Crafts catalystconcentration. The volumetric ratio of catalyst solution to the olefinicreactants used is often about 0.5 to 5:1, preferably about 2 to 3:1. Thepolymerization is advantageously conducted using simultaneous andseparate addition of the catalyst solution and alpha-olefin feed to thereaction vessel.

After the addition of catalyst, phosphorus halide and monomers has beencompleted, the reaction may be permitted to continue for a short periodof time, generally about 5 to 45 minutes, the insure polymerization to abase oil-soluble polymer product, for instance, a normally liquidmaterial which may have a kinematic viscosity at 210 F. of up to about5000 centistokes, preferably up to about 600 centistokes. The reactionmay be quenched using, for example, a lower alkanol, e.g. of 1 to 4carbon atoms, such as methanol or ethanol. The resulting polymer canthen be diluted with a hydrocarbon solvent, such as hexane, and washedwith water, alcohol, dilute aqueous caustic soda, hydrochloric acid,etc.

The novel ashless detergent of the present invention may be prepared bythe condensation reaction of the phosphorylated polymer of alpha-olefinwith an essentially aliphatic polyamine. Suitable polyamines may berepresented by the general formula:

wherein R is a divalent alkylene radical of 2 to 14 or more carbonatoms, preferably 2 to about 7 carbon atoms; R is selected from hydrogenand hydrocarbon radicals such as alkyl, including cycloalkyl, which mayhave, for instance, 1 to about 30 or more carbon atoms, preferably 1 toabout 7 carbon atoms; n is a number from 1 to about 10, preferably about2 to 6. R may extend between two N-atoms, for instance the two to whichR is attached, in which case these nitrogen atoms will have only oneother bond for further attachment. The R and R substituents arepreferably saturated, but may be unsaturated, and may be substitutedwith non-deleterious substituents. Polymers from the reaction ofalkylene dihalides with ammonia or from the polymerization of ethyleneimine are often preferred. A l, Z-diamine, at least one amino of whichis primary, is often preferred and may be represented by the followinggeneral formula:

H R R" n wherein R is selected from hydrogen and hydrocarbon radicalssuch as alkyl, as noted above, or is amino alkyl of l to about 30,preferably 1 to about 7, carbon atoms, and R" is selected from H andalkyl of l to about 12 or more carbon atoms, preferably 1 to about 5carbon atoms. R may also be a hydroxy-alkyl, alkoxy-alkyl or aromaticradical.

Thus, useful polyamines include, for instance, monoalkylenediamines,dialkylaminoalkylamines, polyalkylenepolyamines,N-(p-aminoalkyl)piperazines, etc. Illustrative of suitablemonoalkylenediamines are ethylenediamine, propylenediamine,butylenediamine, octylenediamine, etc. Examples of suitabledialkylaminoalkylarnines are dimethylaminoethylamine,dimethylaminopropylamine, dimethylaminobutylamine,diethylaminopropylamine, diethylaminoamylamine,dipropylaminopropylamine, methylpropylaminoamylamine,propylbutylaminoethylamine, etc. Examples of polyalkylenepolyamines arediethylenetriamine, triethylenetetramine, tetrathylenepentamine,hexapropyleneheptamine, tetrabutylenepentamine, polyamine D (a mixtureof aliphatic and cyclic polyethyleneamines boiling above 340 C. andhaving an average molecular weight nearly the same aspentaethylenehexamine and having as principal componentspentaethylenehexamine, symmetrical and unsymmetricaldiaminoethyltriaminoethylamine, symmetricaldiaminoethyltriethylenetetramine, symmetrical and unsymmetricaldiamineethyl, diarninoethylpiperazine,piperazinoethyltriethylenetetramine, 4-(N-piperazinoethyl)triethylenetetramine, bis-piperazinoethylamine, andarninoethyl (dipiperazinoethane), polyamine H (bottoms frommanufacturing tetraethylenepentamine), etc. SuitableN-(B-aminoalkyDpiperazines include N-methyl-N'-(p-aminoethyl)piperazine,N (fi-aminoisopropyl)piperazine, etc.

In the condensation reaction of the phosphorylated polymer with thepolyamine to prepare the phosphonamide detergent of the invention, thepolyamine is generally reacted in an amount sufficient to provide up toabout 2 moles of polyamine and at least about 0.1 gram atom ofhydrogen-bonded nitrogen, per gram atom of phosphorus in the polymer. Byhydrogen-bonded nitrogen is meant nitrogen of a primary or secondaryamine group of the polyamine, which nitrogen may or may not still bebonded to hydrogen after the polyamine is condensed with thephosphorylated polymer. Preferably, the amount of polyamine will besufiicient to provide at least about 1 gram atom of hydrogen-bondednitrogen for each gram atom of phosphorus.

Thus, for instance, given a phosphorylated polymer having 4 gram atomsof phosphorus per mole of polymer, and assuming thattetraethylenepentamine (TEPA) is the polyamine to be condensedtherewith, there would generally be reacted with 1 mole of the polymerabout 0.08 to 8 moles of TEPA; preferably, however, at least about 0.8mole of TEPA would be employed, thereby providing at least a 1:1 ratioof amino nitrogen to phosphorus atoms. The use of greater amounts ofTEPA in this instance is unwarranted since essentially all of the 4 gramatoms of phosphorous in the polymer would necessarily be diamidated once8 moles of polyamine are reacted therewith.

The phosphonamide-forming condensation reaction is usually conducted ata temperature of about 60 to 320 C., often about 80 to 150 C. Thereaction is conducted to give a base oil-soluble product and often takesabout 0.25 to 24 hours, preferably about 0.5 to hours. Water, HCl oralcohol formed during the condensation reaction is preferably removed asformed.

Water is released during the condensation when the phosphoryl halidemoiety has previously been essentially completely hydrolyzed as, forexample, may occur when the phosphorylation reaction is quenched withwater. Alcohol is released during the condensation when the phosphorylhalide moiety has previously been essentially completely alcoholyzed as,for example, may occur when the phosphorylation reaction is quenchedwith an alcohol. HCl is released during the condensation when, as isoften preferred, one or more halide atoms have been allowed to remain inthe phosphoryl halide moiety as, for example, may occur with onlypartial or no quenching of the phosphorylation reaction with water oralcohol.

The phosphonamidic polymer resulting from the condensation reaction isbase oil-soluble and ordinarily has a kinematic viscosity at 210 F. ofup to about 10,000, preferably up to about 1000, centistokes. Thedetergent additives are added to the lubricating oils in minor,effective amounts, usually in the range of about 0.1 to or more,preferably about 0.25 to 7.5% by weight of the oil.

Lubricating oils which can be used as the base oil or major component ofthe lubricating oil compositions of the present invention include a widevariety of oils of lubricating viscosity, such as naphthenic base,parafiinic base, and mixed base mineral lubricating oils; otherhydrocarbon lubricants, e.g., lubricating oils derived from coalproducts; and synthetic oils, e.g., alkylene polymers (such as polymersof propylene, butylene, etc., and mixtures thereof), alkylene oxide-typepolymers (e.g., alkylene oxide polymers prepared by polymerizing thealkylene oxide, e.g., propylene oxide, etc., in the presence of water oralcohols, e.g., ethylene alcohol), carboxylic acid esters (e.g., thosewhich are prepared by esterifying such dicarboxylic acids as adipicacid, azelaic acid, suberic acid, sebacic acid, alkyl succinic acid,fumaric acid, maleic acid, etc. with alcohols, such as butyl alcohol,hexyl alcohol, 2-ethylhexyl alcohol, dodecyl alcohol, etc.). Thesynthetic oils to which the polymeric phosphonamides may be addedinclude ester-based synthetic oils of lubricating viscosity whichconsist essentially of carbon, hydrogen and oxygen, e.g.,di-2-ethylhexyl sebacate. The above base oils may be used individuallyor in combination, wherever miscible or wherever made so by the use ofmutual solvents. Various of these lubricating materials have beendescribed in the literature and generally their viscosity ranges fromthe light to heavy oils, e.g. about 50 SUS at F. to 250 SUS at 210 andpreferably about 30 to SUS at 210 F.

Other materials normally incorporated in lubricating oils to impartspecial characteristics can be added to the composition of thisinvention. These include corrosion inhibitors, extreme pressure agents,anti-wear agents, etc. The amount of such additives included in thecomposition usually ranges from about 0.01 weight percent up to about 20or more weight percent, and in general they can be employed in anyamounts desired as long as the composition is not unduly deleteriouslyaffected.

The following examples are included to further illustrate the presentinvention.

EXAMPLE I A mixture of normal alpha-olefins of the following approximatecomposition:

was added to a one liter flask equipped with a Dean- Stark trap throughone of two addition funnels which were provided on the flask. A Dry Icetrap was mounted on the Dean-Stark trap to remove and condense from thepolymerization system the volatile solvent, ethyl chloride, used in thepolymerization. To the remaining funnel was charged an ethyl chloridecatalyst solution containing 5.15 grams aluminum chloride and 0.01562mole of phosphorus trichloride per each 100 ml. of solution at 12 C.

Both the olefin feed and the catalyst solution were introduced into thereaction flask simultaneously, the olefin mixture at a rate of 20.4 ml.per minute (0.1095 mole per minute C C alpha-olefin), and the catalystsolution containing phosphorus trichloride at a rate of 40 ml. perminute (0.0155 mole per minute aluminum chloride, 0.00625 mole perminute phosphorus trichloride). The total time for the addition ofolefin and catalyst solution was 12 minutes, and the polymerizationmixture was stirred for an additional 14 minutes. The temperature duringpolymerization was 19 C., and a total of 335 ml. of ethyl chloride (70%)was trapped out of the polymerization system. Methanol (400 ml.) wasadded to quench the catalyst.

The polymer was diluted with hexane and washed with water. After toppingof solvents, the polymer had a KV at 100 F. of 2591.0 cs., a KV at 210F. of 159.3 cs., a phosphorus content of 0.779%, a chlorine content of0.89%, a specific gravity of 0.8762, and iodine number of 15.8 and anoxygen content of 0.49%. The residual unsaturation, shown by the iodinenumber, indicated that the polymerization was terminated by theformation of a double bond with no addition of phosphorus trichloride atthis position.

EXAMPLE II To a 500 ml. reaction flask was added 100 grams of thephosphorylated polymer made in Example I and 7 grams of tetraethylenepentamine. The system was purged with nitrogen over a 10 minute periodas the temperature was increased to 65 C. The temperature was thenincreased to 200 C. over a 15 minute period and was maintained for 30minutes. A 15 cm. vacuum was then applied, while maintaining thetemperature at 200 C., for an additional one hour and 30 minutes tofacilitate the removal of volatiles. The vacuum was then lowered to mm.,and the product was allowed to reach room temperature under the reducedpressure. The polymer was washed with water and stripped of solvents.

The polymer had the following properties.

TABLE I Phosphorus percent 0.708 Nitrogen do 0.36 Chlorine do 0.06 KV at100 F. cs 9344.0 KV at 210 F. cs 383.87 Specific gravity percent 0.8721

Infrared analysis detected amide formation. Since the chlorine contentwas very small, it appeared that the polymer reacted entirely with thepolyamine.

The polymer was tested as an ashless detergent in a 95 V1. Mid-Continentneutral oil in the Low Temperature Detergency Bench Test described inU.S. Pat. No. 3,044,860.

The following results were obtained:

TABLE II Merit rating (100-clean) Base oil 22 Base oil plus 2% additive77 0 to 50 C. with a catalyst solution comprising about 0.5 to 15percent, by weight of the solution, of a Friedel- Crafts catalyst, about0.002 to 0.1 mole of a phosphorus halide, per each ml. of the solution,and an essential balance of a monochloroalkane solvent of 1 to 4 carbonatoms, with the proviso that the amount of the phosphorus halide in thesolution be less, on a molar basis, than the amount of theFriedel-Crafts catalyst in the solution.

2. The method of claim 1 wherein the Friedel-Crafts catalyst is aluminumchloride.

3. The method of claim 2 wherein the temperature is about 0 to 25 C.

4. The method of claim 3 wherein the monochloroalkane solvent is ethylchloride.

5. The method of claim 4 wherein the phosphorus halide is selected fromthe group consisting of compounds having the formulae:

PX PX POX POR'X PR'X; and PR'X;

wherein X is chlorine, bromine or iodine, and R is alkyl, aryl, aralkyl,alkaryl, alkoxy, aroxy, alkaryloxy or cycloalkyl of about 1 to 16 carbonatoms.

6. The method of claim 5 wherein the phosphorus halide is phosphorustrichloride.

7. The method of claim 6 wherein the volumetric ratio of catalystsolution to olefinically-unsaturated monomer is about 0.5 to 5:1.

8. The method of claim 7 wherein the amount and concentration ofcatalyst solution employed provides about 0.1 to 20 percent of theFriedel-Crafts catalyst, based on the weight of theolefinically-unsaturated monomer.

9. The method of claim 8 wherein monomer and catalyst solution arecontacted by their being separately and simultaneously introduced intothe reaction zone.

10. The method of claim 9 wherein the alpha-monoalkene has about 9 to 21carbon atoms.

11. The method of claim 10 wherein the alpha-monoalkene is a normalalkene.

References Cited UNITED STATES PATENTS 3,146,211 8/1964 Errede 260606.5P 3,158,642 11/1964 Chapin et al. 260606.5 P 3,519,607 7/1970 Welch260606.5 P

WERTEN F. W. BELLAMY, Primary Examiner U.S. Cl. X.R.

260-2 P, 94.9 CA

